1. Field of the Invention:
The invention relates to a bushing or internal seal which may be run into a well conduit for effecting sealing engagement with a work string-carried mandrel and may be retrieved by the mandrel when the work string operations are completed.
2. Description of the Prior Art:
There are many operations in the completion of a subterranean well wherein it is necessary to provide a bushing or internal seal in the bore of the production string in order to effect a seal with a work string-carried mandrel. For example, see the bushings 11a and 12 shown in U.S. Pat. No. 4,479,544. While these bushings operate satisfactorily, they have the disadvantage that they must be milled out after the mandrel has been removed and the work string operations completed. This requires expenditure of valuable time which could be utilized for other completion operations or actual production from the well.
The prior art has not provided a bushing which will effect the necessary sealing action in the above-described environment but which may be readily retrieved when the work string-carried mandrel is removed from the well.